Effect of a Biosafety Device on Physico-mechanical Properties of Composite

Objectives: This study aimed to compare, in different periods of time, color stability, surface hardness and degree of conversion of a composite stored in a biosafety device during restorative procedures to other standardized storing devices.
Methods: Esthet-X HD composite (Denstply) was stored in 4 devices: Twist-syringes, Predosed compules tips, Dappen dish and RESTAURASAFE, a biosafety device developed by the authors of this study. In order to evaluate color stability (n=15) and surface hardness (n=15), disc-shaped specimens (10mmx2mm) were immersed in artificial saliva and coffee at 37±1°C for 60 days. The color stability was evaluated using the CIELab system by spectrophotometer (BYK-Gardner) in 8 different periods: baseline, 24 and 48h, 7, 14, 21, 30 and 60 days. Vickers surface hardness was evaluated at the baseline and after 60 days. Degree of conversion (n=5) was assessed using micro-Raman spectroscopy after immersing specimens in saliva (baseline). Hardness and color were evaluated statistically by repeated measures ANOVA followed by the Sidak post-hoc test, and degree of conversion by one-way ANOVA and Tukey post-hoc test (α=.05).
Results: In regards to color stability, no difference was observed for saliva, regardless storing devices (p=0.15) and period of evaluation (p=0.11). For coffee, the dappen dish presented the lowest color stability for both 7 and 30 days (p=0.02). The surface hardness increased after 60 days for both saliva and coffee (p<0.01), regardless storing devices. The predosed compules tips presented lower hardness (48.58±7.04kg/mm²) and degree of conversion (57%) than the RESTAURASAFE when specimens were stored in saliva.
Conclusions: It was concluded that the composite resin stored in the RESTAURASAFE presented similar color stability to twist-syringes and predosed compules tips. Hardness and degree of conversion were higher for the composite stored in the RESTAURASAFE than in the predosed compules tips. RESTAURASAFE provided adequate physico-mechanical properties for the composite resin tested, regardless the period of evaluation.